Annual report pursuant to Section 13 and 15(d)

Accounts Receivable - Accounts Receivable Balance (Details)

v3.21.2
Accounts Receivable - Accounts Receivable Balance (Details) - USD ($)
Apr. 30, 2021
Apr. 30, 2020
Apr. 29, 2015
Sep. 30, 2014
Sep. 16, 2011
Receivables [Abstract]          
Accounts receivable $ 30,264,393 $ 22,786,847      
Long-term contractual accounts receivable (10,249,833) (6,701,136) $ (671,291) $ (772,793) $ (772,793)
Accounts receivable, current 20,014,560 16,085,711      
Less: Allowance for doubtful accounts (3,289,816) (1,758,920)      
Accounts receivable, net $ 16,724,744 $ 14,326,791